There are several algorithms related to image processing which rely on motion detection. For example, the method described in co-pending application Ser. No. 11/509,712, filed Aug. 25, 2006, entitled METHOD, APPARATUS AND SYSTEM PROVIDING ADJUSTMENT OF PIXEL DEFECT MAP, uses motion detection to separate real defects from small elements of the scene in determining the location of defects in the pixel array. As another example, passive continuous auto-focus algorithms use motion detection to control their refocusing procedures.
Simple algorithms for motion detection compare an image of the current frame with a reference frame image and count the number of pixels which are different between the frames. This type of motion detection algorithm, however, requires a large frame memory buffer and, therefore, cannot easily be implemented in system-on-a-chip (SOC) imager systems which have circuit area limitations. Moreover, the large frame memory adds cost to the imaging device.
Accordingly, there exists a need for an improved method and system for motion detection within an imager. There further exists a need for a motion detection system and method which may be implemented in an SOC system.